This fork of Android differs in the following ways:
 - README.android
 - All Android.mk and Android.bp files
 - ALL MODULE_LICENSE_* files
 - libselinux/include/selinux/android.h
 - libselinux/src/android/android.c

All other changes should be upstreamed to selinux as
Android no longer carries changes outside of those files.

The upstream project can be found at:
https://github.com/SELinuxProject/selinux

Thus, since all changes are in separate files, updates merged from
upstream should occur with no merge conflicts.

This fork differs from upstream libselinux in at least the following ways:

* The Android fork omits compiling many of the src files and specifies
  custom build configurations. The exact details, are encoded in the
  Android.bp and Android.mk files.

* The SELinux policy files are all located in / rather than under
  /etc/selinux since /etc is not available in Android until /system
  is mounted and use fixed paths, not dependent on /etc/selinux/config.

* The kernel policy file (sepolicy in Android, policy.N in Linux) does
  not include a version suffix since Android does not need to support
  booting multiple kernels.

* The policy loading logic does not support automatic downgrading of
  the kernel policy file to a version known to the kernel, since this
  requires libsepol on the device and is only needed to support mixing
  and matching kernels and userspace easily.

* restorecon functionality, including recursive restorecon, has been
  been upstreamed as selinux_restorecon(), but there are residual
  differences between it and selinux_android_restorecon().

* Support for seapp_contexts, a new Android-specific SELinux
  configuration file has been added within android.c.

SELinux Userspace
=================

![SELinux logo](https://github.com/SELinuxProject.png)
[![Run Tests](https://github.com/SELinuxProject/selinux/actions/workflows/run_tests.yml/badge.svg)](https://github.com/SELinuxProject/selinux/actions/workflows/run_tests.yml)
[![Run SELinux testsuite in a virtual machine](https://github.com/SELinuxProject/selinux/actions/workflows/vm_testsuite.yml/badge.svg)](https://github.com/SELinuxProject/selinux/actions/workflows/vm_testsuite.yml)
[![OSS-Fuzz Status](https://oss-fuzz-build-logs.storage.googleapis.com/badges/selinux.svg)](https://oss-fuzz-build-logs.storage.googleapis.com/index.html#selinux)
[![CIFuzz Status](https://github.com/SELinuxProject/selinux/actions/workflows/cifuzz.yml/badge.svg)](https://github.com/SELinuxProject/selinux/actions/workflows/cifuzz.yml)

SELinux is a flexible Mandatory Access Control (MAC) system built into the
Linux Kernel. SELinux provides administrators with a comprehensive access
control mechanism that enables greater access granularity over the existing
Linux Discretionary Access Controls (DAC) and is present in many major Linux
distributions. This repository contains the sources for the SELinux utilities
and system libraries which allow for the configuration and management of an
SELinux-based system.

Please submit all bug reports and patches to the <[email protected]>
mailing list. You can subscribe by sending "subscribe selinux" in the body of
an email to <[email protected]>. Archives of the mailing list are
available at https://lore.kernel.org/selinux.

Installation
------------

SELinux libraries and tools are packaged in several Linux distributions:

* Alpine Linux (https://pkgs.alpinelinux.org/package/edge/testing/x86/policycoreutils)
* Arch Linux User Repository (https://aur.archlinux.org/packages/policycoreutils/)
* Buildroot (https://git.buildroot.net/buildroot/tree/package/policycoreutils)
* Debian and Ubuntu (https://packages.debian.org/sid/policycoreutils)
* Gentoo (https://packages.gentoo.org/packages/sys-apps/policycoreutils)
* RHEL and Fedora (https://src.fedoraproject.org/rpms/policycoreutils)
* Yocto Project (http://git.yoctoproject.org/cgit/cgit.cgi/meta-selinux/tree/recipes-security/selinux)
* and many more (https://repology.org/project/policycoreutils/versions)


Building and testing
--------------------

Build dependencies on Fedora:

```sh
# For C libraries and programs
dnf install \
    audit-libs-devel \
    bison \
    bzip2-devel \
    CUnit-devel \
    diffutils \
    flex \
    gcc \
    gettext \
    glib2-devel \
    make \
    libcap-devel \
    libcap-ng-devel \
    pam-devel \
    pcre2-devel \
    xmlto

# For Python and Ruby bindings
dnf install \
    python3-devel \
    python3-pip \
    python3-setuptools \
    python3-wheel \
    ruby-devel \
    swig
```

Build dependencies on Debian:

```sh
# For C libraries and programs
apt-get install --no-install-recommends --no-install-suggests \
    bison \
    flex \
    gawk \
    gcc \
    gettext \
    make \
    libaudit-dev \
    libbz2-dev \
    libcap-dev \
    libcap-ng-dev \
    libcunit1-dev \
    libglib2.0-dev \
    libpcre2-dev \
    pkgconf \
    python3 \
    systemd \
    xmlto

# For Python and Ruby bindings
apt-get install --no-install-recommends --no-install-suggests \
    python3-dev \
    python3-pip \
    python3-setuptools \
    python3-wheel \
    ruby-dev \
    swig
```

To build and install everything under a private directory, run:

    make clean distclean

    make DESTDIR=~/obj install install-rubywrap install-pywrap

On Debian the environment variable `DEB_PYTHON_INSTALL_LAYOUT` needs to be set
to `deb` when installing the Python wrappers in order to create the correct
Python directory structure.
On Debian systems older than bookworm set
`PYTHON_SETUP_ARGS='--install-option "--install-layout=deb"'` instead.

To run tests with the built libraries and programs, several paths (relative to `$DESTDIR`) need to be added to variables `$LD_LIBRARY_PATH`, `$PATH` and `$PYTHONPATH`.
This can be done using [./scripts/env_use_destdir](./scripts/env_use_destdir):

    DESTDIR=~/obj ./scripts/env_use_destdir make test

Some tests require the reference policy to be installed (for example in `python/sepolgen`).

To install as the default system libraries and binaries
(overwriting any previously installed ones - dangerous!),
on x86_64, run:

    make LIBDIR=/usr/lib64 SHLIBDIR=/lib64 install install-pywrap relabel

or on x86 (32-bit), run:

    make install install-pywrap relabel

This may render your system unusable if the upstream SELinux userspace
lacks library functions or other dependencies relied upon by your
distribution.  If it breaks, you get to keep both pieces.


## Setting CFLAGS

Setting CFLAGS during the make process will cause the omission of many defaults. While the project strives
to provide a reasonable set of default flags, custom CFLAGS could break the build, or have other undesired
changes on the build output. Thus, be very careful when setting CFLAGS. CFLAGS that are encouraged to be
set when overriding are:

- -fno-semantic-interposition for gcc or compilers that do not do this. clang does this by default. clang-10 and up
   will support passing this flag, but ignore it. Previous clang versions fail.


macOS
-----

To install libsepol on macOS (mainly for policy analysis):

    cd libsepol; make PREFIX=/usr/local install

This requires GNU coreutils:

    brew install coreutils